Combined internal-combustion and compressed-air engine



May 26,: 1925. 1,539,024

R. W. ROBlNSON COMBINED INTERNAL COMBUSTION AND COMPRESSED AIR ENGINE Filed sept. 27, 1920 5 Sheets-Sheet J May 26, 1925. 1,539,024

R. w. ROBINSON COMBINED INTERNAL COMBUSTION AND COMPRESSED AIR ENGINE Filed 1:. 2'7, 1920 5 Sheets Sheet 2 7'0 AIR MOTOR May 26, 1925 1,539,624

'R. W. ROBINSON admins-minimum COMBUSTION AND COMPRESSED AIR ENGINE 'iledsept. 27, 1920 5 Sheets-Sheet 5 ELL R. w. RCBINSQN m ze. 1925. 1,539,024

' COMBINED INTERflAL COMBUSTION AND COMPBEK'AM 4MB ENGINE May 26. 1925. 1mm

R. W. RQBINSON COMBINED INTERNAL COMBUSTION AND COMPRESSED AIR ENGINE Filed Sept. 27, 1920 5 sheets-sheets Patented May 26, 1925.

(UNITED STATES.

noonron'r WYBRANTS noBINsoN, or MAR-LOW, ENGLAND.

GOMBINED INTERNAL-COMBUSTION AND COMPRESSED AIR ENGINE.

Application filed September 27, 1920. Serial No. 413,129.

(GRANTED UNDER. THE rnovrsroNs or THE Aer OF MARCH 3, 1921, 41 swear. I.., .1313.)

To all whom it may concern: 1 Be it known that I, Roonronr VVYBnANrs ROBINSON, a subject of the King of Great Britain and Ireland, and a resident of Marlow, Buckinghamshire, England, have invented a certain new and'useful Improvement in Combined Internal-Combustion and Compressed-Air Engines, forwhich I have filed application in England June 17, 1919, '0 Patent No. 15,202, and 0t whichthe following is a specification.

This invention relatesto a new or improved internal combustion engine (hereinafter termed the engine) designed to work in combination with an air compressor, compressed air reservoirs, and a compressed air motor (hereinafter termed the air motor) wherein the engine generates energy from fuel and stores it in the formot compressed air in the reservoirs to drive machines in the known manner; the combination according to this invention is characterized by interconnecting the engine and the air motor, without moving gear, but with compressed 5 air in such a way that the working of the engine is controlled by the pressure of theair in the reservoirs, so that the rate at which the engine generates energy is automatically controlled by the rate at which 530 the energy is used by the air motor; by the stroke of the combustion cylinder piston always taking place at the same speed and with the same amount of charge and the sametiming of ignition, delivering the same amount of power whatever maybe the speed of the working shaft of the air motor or whatever the power being delivered by it, the speed of the stroke of the combustion cylinder piston and the time interval between each stroke being independent of one another; by the resistance opposed by the air in the compressor to the stroke of the piston ot the combustion cylinder diminishing during the latter part of the stroke in proportion to the tall of the pressure of the expanding gases so that these gases will still produce power up to a point when their pressure is quite low; and by each stroke of the do its maximum speed immediately on the'explosion of the charge, so that the heat generated will be converted into power before much of it has time to pass into the cylinder walls. I

Other objects in addition to the foregoing 'ing fins.

combustion cylinder piston taking place at general object is to obtain increased power from the internal combustion unit of the apparatus by utilizing the full expansion of the heated gases in the combustion cylinder a and avoiding the use of gearing while at the same time employing means to control the mixture of the fuel and the timing of the ignition to the best advantage in such a way that the speed at which the power is after more fully described, illustrated and claimed. j

A preferred and practical embodiment of the invention is shown in the accompanying drawings in which+ Figs. 1 and 1" are complemental longitu:

dinal sectional views respectively showing opposite ends of the engine, said section being taken through the combustion chamher and the air compressing chamber.

Figs. 2 and 2" are complemental horizontal sectional views ot the construction shown in Fig. 1.

Figure 3 is a vertical cross-seetional View of the combustion cylinder and its surrounding jacket taken through one of the radiat- Figure 4: is an end elevation of the combustion chamber and of the device showing one form. of means employed for controlling the ignition and exhaust automatically by air pressure from the main reservoir.

Figure 5 is a detail side elevation of the construction shown in Figure Figures 6 and 7 are respectively front and side elevations of an alternative form of means for accomplishing the same result as the construction shown in Figures 4; and 5. a

Figure 8 is a diagrammatic view illustrating the relative positions of the control cams in full and dotted lines when actuated by the main rocking shaft of the device.

The same letters in all the figures rep resent the same parts.

In Figures 1, 1 and 2 and 2, the piston o of the combustion cylinder is connected to the crank lever a on the rocking shaft (Z,

and the piston Z2 of the air-compressing cylinderwhich is of larger'bore than the combustion cylinder and about thesame stroke, is connected to a similar crank lever on the same rocking shaft. The crank levers and the connecting rods are in the positions shown at the end of'ther stroke of the combustion cylinder, the dotted lines representing their positions at'the beginning of the stroke. This arrangement gives the piston or the combustion cylinder an increasing mechanical advantage over that of the air-compressing cylinder towards the end.

of the "stroke. 'In the arrangement shown,

the air-compressing cylinder is placed inside I the compressed air reservoir 0, 6 is an air valve for the admission. of air to the cylinderb,'and b is an air valve through which the air compressed by the stroke of the piston Z) is admitted to the reservoir 0.

lVhenthe inlet port is of the combustion.

the air in the cylinder 7) is at tirst slight,

though at the beginning of the stroke the piston 7) has a mechanicaladvantage over the piston rt. With the cylinders proportioned and the crank levers set as shown, when the piston a has reached stroke the piston 72" will reach a. little over stroke, producing a pressure of over 30 pounds in the cylinder 6, and as at this point the piston a will have'only justattained to a slight mechanical advantage over the piston b, the pressure in the cylinder Z) will equalizea pressure of about 60- pounds in the cylinder 0!, and from that point to the end of the stroke the mechanical ,advantage of the piston a over 7) increases rapidly. The bore and stroke of the combustionv and compression cylinders, and their relative proportions would be regulated by the amount of pressure to be carried in the main reservoir.

VVhe-n thecharge admitted to the combustion cylinder is suflicient, on being ignited, to drive the pistons a. and Z) to the end of their stroke, thereby completing the compression 0 the air in Z), and forcing itinto the reservoir 0. the inlet port 70 of the combustion cylinder is closed and the charge tired as will presently be described.

Asmaller air reservoir cliigure 2surrounds a cylinder-e whose piston c is connec'ted to another crank'lever c on the-rocking shatt d, so adjusted that the action or" the piston e is opposed to that of the piston a and when the exhaust port 01? the combustion cylinder is opened at the. end

of the combustion stroke, the pistons a and b :are; driven back throu'ghtheir; return stroke by" the action of the piston e which is driven forward by the compressed air in the reservoir-'0, which is kept at sufficient pressure for the purpose by the reducing valve'othrough which the reservoir 0 is in communication with the main reservoir 0. The cylinder 6 exhausts back into the reservoir c, with which it. communicates by means of a port or ports 6 which are closed by the piston 6 just, before it reaches ;t he end. of its return stroke, through which it is driven bythe: next stroke of the combustion. cylinder; so that it, through incorrect adjustment of the valve mechanism of the combustion cylinder, the charge admitted should be ,more, than .suflicient to compress the air in the compression cylinderinto the reservoir, the air cushion thus formed in the cylinder 6 will take up the surpluspower generated.

The crank lever b isso setthat. the normal end: of its stroke is on the dead centre as regardsthe piston. b, which, therefore, can never be, driven against the end of. the cylinder 7)". The end of the cylinder e, where the air cushion is formed. isconnected. to the reservoir 0 by a one-way valve 6 by means of whichthepressurein the reservoir quickly. starts thestroke. The bore of the cylinder 6 for. a short distance at its outer end is less-than that oi therest of the cylinder, the outer end of the piston (5 corresponding to this smaller bore, so that at the end of the outward stroke there; is also an air cushion formed which checks the strokebefore the piston a reaches the end of the, combustioncylinder.

There is another secondaryair reservoir supplied :trom the main reservoir through a second reducing valve 0: and the small cylinders which actuate the admission andexhaust mechanism of the combustion cylinder and also. the firing of the charge, are worked by air pressure supplied. from this reservoir, thereducing valve otwhich keeps the pressure at a suitable point for thispurpose which may be considerably lower than that in the main reservoir. The air is led from the reservoir 0 to the valve mechanism by the pipe f l igures 2, 4, 5, 6, and 7.

In Figure at, the air gauge cylinder at is connected-by the small pipe 7" to the pipe f andthrough that to the ma n reseryoir 0, and is provided witha long piston a. The amount of air pressure necessa y to move this piston forward is regulated by the compress on of the spring a and adjusted by the nut n to that which it is desired to maintain in the main reservoir. Thepiston a, is provided with an annular groove a which, when. in the position shown, allows the compressed air from the pipe f to enter the valve chamber 9 and through it the cylinder but when the pressure in the main reservoir rises above the predetermined point the piston u is driveii forward and the groove a passes beyond the port a connected with the pipe f cutting off that pipe from communication with the cylinder 9. The pipe f is always in communication with the cylinder h. v

The pistons g and h are attached to opposite ends of a common piston rod and the area of the piston g is double that of the piston h. The combustion cylinder at is provided with a common inletand exhaust port is opening into the cylinder ofthe piston valve 7', 7". The inlet and exhaust port is is opened and closed by valves which are conveniently of the piston pattern as shown in Figures 4 and 6. In Figure 4:, the pistons 7' and j are of the same diameter, but in a the alternative construction shown in Figure 6 the piston j is larger than j.

An admission pipe (not shown) from the carburetter Z opens into the piston valve cylinder between the pistons j and j through the port m which is always between the pistons j and y" throughout the length of their stroke. Figure 4 shows the port is open to the exhaust pipe at. The piston valve 7', j is actuated by the pistons g and. it through the connecting lever j and it stands in the position shown in Figure 4 as long as the pipe f is cut off from the valve chamher 9.

When the pressure in the main reservoir falls enough to cause the gauge piston u to admitair from the pipe f to the cylinder 9, the piston g is immediately driven through itsfull stroke and the piston valve j consequently driven through its full stroke thereby bringing the port between the pistons j and 7" and admitting the com-f pressed fuel charge from the carburetter to the combustion cylinder, the piston a of which, Figures 1 and 2, is thus driven forward. The consequent motion of the rocking shaft cl, Figures 1 and 2, is communicated to the valve rocking shaft 2', Figures 4t and 5, through the crank lever Z Figure 2 and the connecting rod 2' and thusto the cams 0, 0, 0 and 0 Figures at and 5. The position of these cams and of the lever a" at the beginning of the stroke of the com:

bustion cylinder are shown in Figure 8, the

dotted lines representing their positions at the end of the stroke. Immediately after the start of the stroke of the combustion cylinder the admission port of the cylinder 9 is closed by the valve 72 through the motion of the cam 0 and the lever s and the earn 0 is so timed that it opens the exhaust valve of the cylinder 9 when the correct charge has been admitted to the combustion cylinder. causing the piston valve, driven by the piston in to close the admission port is. The piston valve is brought to rest at its half stroke bythe cushion of air in the cylinder 9 after the piston 9' passes theexhaust port '9 at which point the piston j covers the port 1 0, as shown in Figure 6, in which this part of the vpiston valve is the same as in Figure 4, and the stud 7' on the lever 7' trips the pawl 9, thereby closing the ignition circuit, and thechargeisfired.

At or near the end of the stroke of the combustion cylinder the secondexhaust port 9 of the cylinder 9 is opened by the cam 0 allowing the piston & to complete its stroke and thus open the exhaust port 70,

when the pistons a 'and Z2 Figures 1 and 2,"

are driven through their return stroke by the action of the piston 6 as already -degauge piston a allows air from the pipe 7"? to enter the cylinder 9 the cycle will be repeated, but if the pressure in the main res- .ervoir has been sufliciently raised to force the piston u? beyond the port a of the pipe F, the internal combustion part of the machine will rest till this port is again opened by the falling of pressure in the main reservoir. WVhen the engine is running at a constant speed below its maximum out-put the gauge piston 11, will keep the port a partly open and the pistons and k will make a slower stroke, but when the inlet port is is opened the stroke of the piston in the combustion cylinder and that of the pistons and 71, will always be at their maximum speed. The cams 0-,, 0 0' 0 are seton the rocking shaftz' at about their correct advance and the exact adjustment of the timing of the valves 19, 19 p and the lever 7' can then be made while the engine is running by means of the slides t, which are then locked in correct position by the thumbscrews t 1 I p The cam 0 is so set that it will cause the lever 1", Figures 4: and 5, to break the ignition circuit at r immediately after the contact is made at q, so that it, through the sticking of a piston or in any other way, the inlet port 1c should be prevented from closing at the correct time and too large a charge should therefore enter the combustion cylinder, ignition will not take place on the closing of the circuit at g and the charge will not be fired, but will pass out through the exhaust by the automaticworking of the arrangement about to be described.

A small passage z-Figure 4c-connects the chamber of the exhaust port g with that of 9 this passage being throttled by a thumbscrew valve z Figures 4, 5 and 7. When the piston g is brought to rest at half i11derabove=the.-piston-.valvenir -fere1 with the normal:

stroke by; the, air remaining in the cylinder 9 it there should beamisfirmflthe ziir in: g will-exhaust by thetpassage;zijthrough the n port 9 allowing the :piston '71 .to complete,-

its sti:ol eand: .open the exhaust ports-Jr Ofv the combustion:cylinder1whenuthe-cycle will be-repeated. The :thumbscrew valve 121i is adjusted so that the exhaust through the passage a will notrbe fast: enoughaito inter- If the ignitioncircuit should break down, a after a few. misfires the pressurein :the main 1 reservoir Will falll enough to I oause the gauge piston u :to cut =ofi therconnection' between the pipeftand the. valve chamberqg -mbyi moving theannular. groove utin the reverse direction 1 from its normal motion i when: closing-the port, and-thus stop the engine with only a'slightfall of. pressure invthe'main reservoir allowing the engine :tOfbB started again, when the ignition circuit has been-ad-i 1 j usted by pressing thei nut it? against 11 its spring; w" 1= 1'. 1. M11191 H2 The exhaust port 9? of the cylinder 9 and.

the: pore-connectingthewpipe: f? withrthe cylinder h are set a.;littletout from the lOyl-L inder ends so :that .the pistons. are brought to rest, on =ain-cushionsat, the. end: of their strokes, andgtheend of the-cylinder h is con-' nected'with the pipe f by acne-way valve tov ensure the :quick starting of its'stroke; The sparking -plugwyFigures 4: and. 6, is inserted in the, end otthelcomb-ustion oyl-x The top of the fuel-tank y, Figure l, is. connected-tothe air pi pe. f by a 'small pipe; 3 thus' equalizing the pressureybetween' tank and-@carburetter; thisx-pi pe extends a.

short distancewin'side the pipev 7% Figures 4' a and 6, its= -open-Iend meeting theifiow of air. on its way'to the carburetter, son-that when the air, charge passes through thezcarbu-z retter, there is no :Eal'l of pressure in the tank. I

The pipe: 7, FiguresQ leads the compressed air from the main reservoir 0' to-thejacketof thecombustion cylinder at, where it circulateszround the spaces between the fins (L passing-from one space to the next-through the -apertures afiFig-ure 3, in tl1e-fi11s ;tl1e aperture in e'ach fin'being on. the opposite sideofthecylinderfrom .those; in the fins on either sidefxof it. The

compressed air having thus taken up: the heat from the cylinder walls, passes outrof theother end of the: jacket through the pipe n, 'whichi-is'carried down the inside of the exhaust pipe m to the cylinders of the air niotor, these cylinders. being alsofitted with jackets through: which the-exhaust gases pass, keeping. them at. a high enouglr it-emperature to flee worked by the superheated compressed air tolthe best advantage."

. Thepipe-fflFigures-Qand2 .extends into workinglof the piston. 1

the main reservoir 0 andis closed at the end, the compressed air passing into. it through transverse slots in its sides.'--..Round the end of this pipe'is a. cylinder w'fitted with corresponding slots and having a short sliding motion: onothe pipe The cylinder ne isaattached to thepiston :wof "the gauge cylinder 10 which is connected with the main reservoir -bya one-way valve 40 and is .providedwith a small relief cock. wt A quick opening-and closing of the-relief cock,

when-thepressure.in-thevreservoir is at its maximum,willcause the-piston wt to draw the cylinder w-to the end of its possible-motion, in which position: the slots-yin the-cylinder registermw-ith:those in the pipe-and its piston wwill-move forward so-as to.

equalize the pressure oneachsideot it and will move the slots in. the cylinder w out of register withthose in the pipe f and -.throttle t'heflow. of compressed airto the air -motor, and it will thus automatically prevent:

more: air being used by the amotor than the internalcombustion part can supply. ==The amountof the motion of the piston w for agiven fall of 'pres'surefwilldepend on the vol'umefiotain in==the cylinder 'w which is adjusted so that.:=thepressure in the main :I'QSGPVOlI-WWlll not fall. low. enoughto permit the 'gaugecylinder u, Figure 4, tocut off the pipe f from the cylinder g. a

The pipe f is-provided with a throttle by which the air motor is started and its ispeedcontrolled and the pipef is provided witha stop cock which can be closed when the engine ii'sstopped for any length of: time; this stop CO CkdS placed. between the small pipes f and y andthe main reservoir; A stop cock is 'alsoplaced in thepipe f construction to that shown in Figures 4 and 5 and described above-.=. In Figure-.Qthe piston 7' of'the piston valve is-of larger diameter than thepiston j and is driven towards its end of thepiston valve cylinder bythe pressure-ofits charge.- .;It is driven in the opposite direction by compressed air admitted to the; cylinder throughthe valve chamber gt from the pipe 7? in the sameimanner Figures G and Trepresent an alternativev as it -isadmitted to the cylinder 9, Figure 4.

The inner; BIlClzOf thispiston corresponds to the'vbore' of the smallerend of the piston valve; cylinder, thusprovidingan. air cushion .to check the stroke in that-direction, the air cushion at the other end being arranged for as in the cylinder 9, Figure at. The length of the piston 7' is such that its inner end will not uncover the port 9 The working of the valves 79, 72 p and of the circuit breaker r by the cams 0, 0 0 and 0 is the same as described for Figures a and 5. The stud j Figure 4, is replaced in Figure 6 by a disc attached to the end of the rod of the piston valve which passes through a stuffing box in the end of the valve cylinder, the disc j tripping the pawl g.

In Figures 6 and 7 the make and break of the ignition circuit can take place as shown, the circuit being closed by the contact between the levers g and r or it may be arranged by two contacts as in Figure 4, or in any other suitable manner. In this construction there is a small port connecting the valve chamber 9 with the gauge cylinder u and so placed that the groove 14 will connect these two ports after it has closed the port a to the pipe f so that if the engine should be stopped for any length of time with the stop cock in-the pipe f standing open and some of the charge should leak past the piston j the leakage will escape by these small ports and thus be prevented from moving the piston valve.

Figures 6 and 7 show the positions of the piston valve and air valves at the moment of ignition, when the piston j covers the port is.

In both designs there is an annular depression around the centre of the piston j, which depression stands opposite the port when the charge is fired, so that the part of this piston exposed to the heat of the explosion does not come into contact with the walls of the piston valve cylinder. j

The valve 10 Figure 2, and the relief cock w of the gauge cylinder e0 may be replaced by a coil spring similar to that of the gauge cylinder a, Figure 4, and adjusted in the same manner to the correct pressure to correspond to that carried in the main reservoir, but the arrangement described above would needless attention as it automatically adjusts the pressure in the cylinder to that in the reservoir.

I claim 1. A combined internal combustion engine and air compressor including oppositely located internal combustion and air com-' pressor units, a rock shaft common to said units, a. main compressed air reservoir in communication with the air compressor, an auxiliary reservoir, an auxiliary piston adapted to be actuated by pressure supplied from said auxiliary reservoir to return the pistons of the internal combustion engine and air compressor to their outward position after their working strokes, a source of fuel supply for the internal combustion engine unit, an air linebetween the main com pressed air reservoir and the internal combustion engine, said air line communicatin with the said source of fuel supply and means controlled by the drop of pressure in the main reservoir for supplying a fuel charge to the internal combustion engine unit and igniting the same' 2. An apparatus of the class described including an internal combustion engine and and the compressor to the beginning of the working strokes, and means also operated by said crank shaft for controlling the'valves of the internal combustion engine.

3. An apparatus of the class described including an internal combustion engine having a jacket provided with a circuitous passageway, an air compressor including a main reservoir, an auxiliary reservoir in connection with the main reservoir,reciprocating pistons respectively for the internal combustion engine and air compressor, and piston and cylinder means operated by the air pressure in the auxiliary cylinder for operating said pistons of the engine and compressor on the return stroke, and a conduit from the main reservoir to the casing of the internal combustion engine whereby the compressed air absorbs heat from the engine.

4. An apparatus of the class described 'including a jacketed internalcombustion engine, an air compressor having a main air storage reservoir, a compressed air conduit connecting the main reservoir with the jacket of the internal combustion engine, and an automatic regulator device for controlling the supply of air from the main reservoir to the said conduit whereby air willnot be permitted to escape from the main reservoir faster than the internal combustion engine can compress and supply it.

5. An apparatus of the class described including ajacketed internal combustion engine, an air compressor having a main air storage reservoir, a compressedair conduit connecting the main reservoir with the jacket. of the internal combustion engine, and an automatic regulator device for con-v trolling the supply of air from the main reservoir to the said conduit whereby air will not be permitted to escape from the main reservoir faster than the internalcombustion engine can compress and supply it, said automatic regulator comprising a sleeve haying openings and adapted to register with openings in a compleinental member which communicates with the conduit leading to the jacket of the cylinder, a cylinder in valved communication With the main reservoir, a piston in said cylinder and connected with said sleeve, and an atmospheric valve communicating with said cylinder.

6. An apparatus of the class described including an internal combustion engine, and an air compressor device, said device comprising a main compression cylinder and a main storage reservoir, piston and cylinder i'neans for returning the pistons of the engine and compressor to the beginning of their Working strokes an auxiliary reservoir communicating with the main reservoir and adapted to supl'ily air to the said piston and cylinder means, a low pressure reservoir also in communication with the main air storage reservoir, valve means for the internal combust-ion engine, and means including the pipe-line in communication with the low pressure reservoir for operating said valve means a car'bureter for the internal coinbustion engine, a conduit between the carbureter and the main air storage reservoir, a fuel tank for the oarbureter, and an air pressure line between the conduit connecting with the main reservoir and the said fuel tank.

In testimony whereof I have affixed my signature here-to this 6th day of September, 1920.

R-OCHFORT WYBRANTS ROBlNSON. 

